Thread cutting and holding device for sewing-machines.



W. L. BARRON.

THREAD CUTTING AND HOLDING DEVICE FOR SEWING MACHINES.

APPLICATION FILED SEPT. 6. 1913.

Patented July 24, 1917.

2 SHE ETSSHEET I.

WITNESSES:

W. L. BARRON. THREAD CUTTING AND HOLDING DEVICE FOR SEWING MACHINES.

APPLICATION FILED SEPT. 6. 1913.

Patented July 24, 1917.

2 SHEETSSHEET 2.

an. o.

WILLIAM LUTHER. BAERUN, OF NEW YORK, N. Y., ASSIGNOR TO THE SINGER.MANU- FACTURING- COMJPANY, A CORPORATION OF NEW JERSEY.

THREAD CUTTING AND HOLDING: DEVICE FOR SEWING-MAUHINES.

asagna.

Specification of Letters Patent.

0 application filed September 6, 1913. terial N0. teases.

To all whom it may concern.

Be it known that I, WILLIAM L. BARRON, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Thread hitting andHolding Devices for Sewing- Machines, of which the following is aspeclfication, reference being had therein to the accompanying drawings;

My invention relates to automatic devices for two-thread sewingmachines, adapted to sever the threads at the completion of a stitchingoperation and to nip or hold the ends of the needle thread and shuttlethread during the formation of the first of anew group of stitches toinsure proper interlocking of said threads. Such devices are illustratedin the patent to Gatchell, No. 798,130, of August29, 1905, and in myapplication for patent filed February 7, 1913; Serial.

No. 746,696. The object of thepresentinvention is to improve theaforesaid devices and particularly the means :tor'nipping the shuttlethread.

In the present instance, the invention is applied to a Singerlock-stitch machine for sewing on buttons. The cutting and nippingelements include a tapered shuttlethread blade and a taperedneedle-thread blade, a shuttle thread nipping finger and a needle threaddrawing hook-all carried by a carrying arm pivoted to the under side ofthe throat-plate of the sewing machine. The carrying arm has a sectorgear which meshes with a cam-actuated rack, and said cam, in conjunctionwith a stop-motion clevice, serves to impart positioning, cutting andnipping-movements to the elements.

The needle thread drawing hook is given its initial operative movementwhen the machine is started to form a group of stitches. The passage ofthe shuttle through the needle-thread loop first presented, draws theloose end of the thread down through the needle-hole; and the movementof the drawing hook serves to carry the loose thread into engagementwith two membersv supported by the throat-plate, whereby the firstmember, a clamping jaw, nips the needlethread and the second member, aknifeedged notched plate, severs its loose end. A cam surface on thehook holds the springretracted clamping jaw against the thread until twoormore stitches are formed, when a second movement of the hook releasesthe tuated rack causes a forward movement of the carrier-arm whereby thelower threadis seized by the shuttle-thread blade, the

needle-thread blade being moved close to the Patented July tat, 119M.

needle-hole. The'needle descends, and, as

it rises, a second movement of the carrying arm causes the seizure ofthe needle thread loop by its blade, whereupon the final orthread-severing movement of the blades is effected, the rack andcarrying arm being given a quick movement by a stop-motion lever, whenthe latter is operated to stop the machine.

In devices of the present type the shuttlethread when left loose at thecommencement of a new group of stitches will frequently draw through oneor more of the needlethread loops. To obviate this difliculty thepresent invention provides simple and effective means to nip the shuttlethread be fore the cutting operation in such manner as to securely holdwhat would otherwise be the loose end of the thread. The presentconstruction renders unnecessary the employment of a cam-plate andsliding or swinging hook which form the subject of the patent toGatchell above referred to. Ihe means employed in the present invent1oncomprise aspring nipping-finger car ried by the blade-carrying arm andso shaped and positioned with respect to the shuttle-thread blade thatthe movement of the latter is employed to nip the shuttle thread betweenthe lower face of said blade and the nipping finger.

In the accompanying drawings, Figure 1 is a side view of a button sewingmachine embodying the present invention. Fig. 2 is a bottom view of thesame. Figs. 3 and 4: are bottom plan views of the thread-nipping andsevering attachment with the parts in dili'erent positions. Fig. 5 is aperspective view of the attachment with the parts in position after therelease of the needle thread and shortly after the commencement of astitching operation. Figs. 6 and 7 are sections of Fig. 3 at lines 66and 77, respectively. Fig. 8 is a perspective View of the shuttle-threadblade and nipping finger showing the position of the shuttle-threadimmediately prior to the severing thereof. Fig. 9 is a perspective viewof the needle thread clamp and part of the needle-throat.

In the present instance the invention is applied to a Singer lock-stitchmachine for sewing on buttons. As shown, the machine comprlses thestandard 1, overhanging arm 2 and head 3, the latter supporting avertically reciprocating needle-bar operated from the driving shaft 4.An oscillating shuttle is fitted withinthe shuttle race 5supported'below the bed-plate 6, said shuttle idly attached sto -motioncam 11. "Pivot ally mounted at its lower end in a pro ection ,12 "fromthe standard is a start and stop-motion lever 13 provided with a beltshifting arm 14 andwith spring-pressed plunger 15. The stop-motion lever13 is spring-pressed toward its rearward or oper ative position, and isdetained in its forward or inoperative position by a detentlever 16'which is. maintained normally in operative engagement with the upperportion of thestop lever by means of the spring V 17 in a well-knownmanner. The stop-lever '13 is so mounted within the projection 12 as tobe capable of slight sidewise movement against the spring-pressedplunger-p1n'l8,

' shown in end view only in Fig.1.

' The thread-cutting and nipping elements are carried beneaththe throatplate of the.

machine as shown in Figs. 3, 4 and 5. -The shuttle-thread blade 19 andthe needlethread blade 20 are fixed upon swinging arm 21 carryingsector-gear 22,. which gear is journaled upon a pin 23- within a bracket24 ifastened by means of screw-stud 24 to the under side of thethroat-plate 25. Rigidly secured to the arm 21 is a thread-drawing armor hook 26 disposed adjacent the under side of the throat-plate andformed at its forward end with a barb 26 As shown in Figs. 3, 4 and 5the under side of the throatplate is recessed at 27 to accommodateclamping jaw 28 pivoted at 29 and normally held out of engagement withfixed jaw 30 within recess 27 by spring 31.

Meshing with sector-gear 22 is a rack 32 formed upon a lateral armattached to sliding bar 33 supported beneath the bed of the machine andhavingnear its rearward end a block 34 formed with a lateral notch. Thisnotchis entered by the contracted lower end of a lever 35'pivotallymounted upon ful crum-stud 36 carried by a bracket 37 supported by thebed-plate of the machine, said I lever being provided at its upper endwith a roller-stud 38 entering cam-groove 39 in the face of rotarycam-wheel 40, the latter being mounted upon the standard 1. Camwheel40'is provided with a worm-wheel 41 meshing with a worm 42 fixed uponthe main-shaft 4. The block 34 has a rearward extensioncarryingaroller-stud 43 embraced reassess,

by the forked arm of a bellcrankslever 44 fulcrumed at 45 and having asecond arm provided with a-spring-pressed pin 46 entering aslot 47 inthe lower end of stoplever 13. The lever 35 and bellcrank-lever 44.serv'e, through the connections above described, to impart operativemovements to the thread-cuttingand nipping elements," as more fullydescribed in patent to Horton, No. 807,676,0f December 19, 1905.

i y In Fig, 3 vtheparts are shown in the position they assume when themachine is started to form a group of stitches. When the needledescends, the loose end ofthe needlethread is above the work-plate, butthe passage of the shuttlethrough the loop of needle-thread draws thesaid loose end down through the needle-hole. rises, cam-follower, 38travels over the inclined cam section 48 thereby moving lever 35 and itsconnections with sector-gear 22 to impart an initial rotary movement tothe latter.

' The movement of sector-gear 22 will swing thread-drawing arm or hook26 so that its hook will cross the needle-hole .50

" thereby engaging the loose end of the needlethread and drawingthelatter to one sideas shown in Fig. 7 and between the nipping aws 28 and30. When the thread is so placed, a cam surface 26 formed on thethread-drawing arm or. book will engage .wheel. The hook 26 maintainsits position (Fig. 4) to hold the clamp closed until two As the take-upor more stitches are formed, whereupon follower 32 leaves the dwell ofthe cam and reaches the inclined section 51 of the'cam groove. At thispoint the hook is given a second movement which carries the parts to theposition shown in Fig. 5, the needlethread being released by theretraction oil clamp-jaw 28.

The parts are held in the position shown in Fig. 5 by dwell 52 in thecam until the close of a stitching operation, when the follower leavesdwell 52 and reaches an inclined section of the cam-groove. At thispoint the carrying arm and blades 19 and 20 will be advancedsufficiently to enable blade 19 to engage the shuttle-thread. The bladeswill then have a short period of rest while the follower is on a shortdwell and will then moveso that, on the next descent of the needle,blade 20 will engage the nee- 1 dle-thread loop, and the two threadswill be aeaeaa severed by the overthrow of the stop -lever at a pointwhen follower 38 reaches a dwell section in the cam. That is to say, theblades 19 and 20 will be given a quick movement to their extremeforwardposition to sever the thread and will then be restored to the initialposition shown in Fig. 3, as fully described in the patent to Hortonabove referred to.

A description will now be given of the means for nipping the lower orshuttle thread to which the present invention more particularly relates,the foregoing tion of the elements used in connection with said nippingmeans being necessary to a complete understanding of the invention.

Mounted upon carrying arm 21 and fastened thereto by means of screw 57and pin 58 is the shank 59 of a spring nipping finger 60 which is heldagainst the lower face of shuttle-thread blade 19 and which, at itsouter end, is depressed and ofi'set from the edge of said blade. Whenthe shuttle thread is seized by blade 19 in the movement of the partsfrom the position shown in Fig. 5 to the position shown in Fig. 4:, saidthread is drawn over the tapering point of the blade until that portionleading to the shuttle passes between the blade and the offset point ofspring nipping-finger 60.

The succeeding movement of blade 19 to cutting position, as shown inFigs. 3 and 6, is utilized to draw the shuttle thread between the lowerface of the blade and the upper spring-pressed face of the nippingfinger. The thread leading from the shuttle is held firmly between thefinger and the blade when the parts are given a quick forward cuttingmovement by the overthrow of the stoplever, as previously described, andlikewise uring a corresponding return movement of the parts to theinitial position shown in Fig. 3. The shuttle-thread'is held by thenipping elements during the movement of the parts to the position shownin F 4, which effects the nipping of the needlethread and the severingof its loose end, and until several stitches of a new group are formed,the feeding of the work above the throat-plate serving to withdraw theshuttle thread from the nipping finger as will be understood withoutfurther expianation.

Having thus set forth the nature of the invention, what I claim hereinis 1. In a sewing machine, the combination with stitch-forming devices,of a movable thread-cutter for severing the thread, and means fornipping the thread before a thread cutting operation comprising anipdescripping finger carried by and cooperating with said thread-cutterin nipping the thread between itself and the adjacent face of thethread-cutter.

2. In a sewing machine, the combination with stitch-forming devices andav movable thread-cutter for severing the thread, of means for nippingthe thread before a thread cutting operation comprising a spring nippingfinger moving with said thread-cutter and pressed toward one facethereof against which it is adapted to grip the thread.

3. In a sewing machine, the combination with stitch-forming devices of amovable thread-cutter for severing the thread, a spring nipping fingersustained in fixed position relatively to said thread-cutter, and meansincluding said thread-cutter for guid ing the thread between its faceand the nipping finger before the thread cutting operation.

4:. In a sewing machine, the combination with stitch-forming devices anda movable thread-cutter for severing the thread, of a swinging supportfor said thread-cutter, and a nipping finger carried by said swingingsupport and spring-pressed against one face of said thread-cutter, theouter end of said finger being bent from the face of the thread-cutterand offset to form a threadguide.

5. In a lock-stitch sewing machine having a needle and a shuttle andmaking a predetermined number of stitches, means for nipping andtrimming the beginning end of the needle-thread at the start of thecycle of operations, means for cutting the finishing ends of theneedleand shuttle-threads, and means for nipping the shuttle-threadtoward the end of a cycle of operations, said lastnamed means beingmovable with the means for cutting a finishing end of thread.

6. In a lock-stitch sewing machine having a needle and a shuttle andmaking a predetermined number of stitches, means for cutting thefinishing ends of the needleand shuttle-threads, and means for nippingthe shuttle-thread toward the end of a cycle of operations, saidlast-named means being movable with the means for cutting a finishingend of thread.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

WILLIAM LUTHER BARRON.

Witnesses:

Grim L. TERNA, W. LEE HELMS.

